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Discovering High-Quality Threaded Discussions in Online Forums

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Journal of Computer Science & Technology 2014年第3期29卷 519-531页

作者： jung-tae Lee Min-Chul Yang Hae-Chang Rim Department of Computer and Radio Communications Engineering Korea UniversitySeoul 136-713Korea

Archives of threaded discussions generated by users in online forums and discussion boards contain valuable knowledge on various topics. However, not all threads are useful because of deliberate abuses, such as trolling and flaming, that are commonly observed in online conversations. The existence of various users with different levels of expertise also makes it difficult to assume that every discussion thread stored online contains high-quality contents. Although finding high-quality threads automatically can help both users and search engines sift through a huge amount of thread archives and make use of these potentially useful resources effectively, no previous work to our knowledge has performed a study on such task. In this paper, we propose an automatic method for distinguishing high-quality threads from low-quality ones in online discussion sites. We first suggest four different artificial measures for inducing overall quality of a thread based on ratings of its posts. We then propose two tasks involving prediction of thread quality without using post rating information. We adopt a popular machine learning framework to solve the two prediction tasks. Experimental results on a real world forum archive demonstrate that our method can significantly improve the prediction performance across all four measures of thread quality on both tasks. We also compare how different types of features derived from various aspects of threads contribute to the overall performance and investigate key features that play a crucial role in discovering high-quality threads in online discussion sites.

关键词： online forum discussion board thread quality

Environmental friendly synthesis of hierarchical mesoporous platinum nanoparticles templated by fucoidan biopolymer for enhanced hydrogen evolution reaction

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Journal of Materials Science & Technology 2020年第11期42卷 185-190页

作者： Seung Man Lim Kyunglee Kang Hongje Jang jung tae Park Department of Chemical Engineering Konkuk University120 Neungdong-roGwangjin-guSeoul 05029Republic of Korea Department of Chemistry Kwangwoon University20 Cwangwoon-roNowon-guSeoul 01897Republic of Korea

Researching novel hydrogen evolution reaction(HER)catalysts with enhanced electrocatalytic activity,excellent stability,and cost-efficiency is of great significance for the large-scale hydrogen production from industrial electrolysis *** report the preparation of hierarchical mesoporous-Pt nanoparticles(HM-Pt NPs)with coral-like rough surface morphologies using environmental friendly and biocompatible fucoidan(Fu)biopolymer as a surface engineering compound and its application to electrocatalysts for *** designed HM-Pt NPs yields better mass activity of electrocatalysts compared to a commercial Pt/***-Pt NPs showed an overpotential of 33 mV at 10 mA cm-2 for the HER in 0.5 MH2SO4,which was highly comparable to that of the commercial Pt/C catalysts(29 mV).However,the amount of HM-Pt NPs loaded in glassy carbon electrode(0.033 mg mL-1)was approximately 20 times lower than that of the commercial Pt/C(0.64 mg *** HM-Pt NPs also maintained high catalytic stability with a consistent HER current density after 1000 continuous *** excellent HER performance is attributed to the improved electrochemical surface area,highly porous structure,and good surface wettability of the HM-Pt NPs,which results in enhanced electrocatalytic activity,decreased resistance at the electrode/electrolyte interface,and facile penetration of the electrolytes inside the electrode.

关键词： Mesoporous Fucoidan Biopolymer Low Pt content Hydrogen evolution reaction

High-Speed,High-Power Motor Design for a Four-Legged Robot Actuator Optimized using the Weighted Sum and Response Surface Methods

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CES Transactions on Electrical Machines and Systems 2021年第3期5卷 224-231页

作者： tae-Woo Lee Do-Kwan Hong tae-Uk jung the Energy and Power Conversion Engineering Department University of Science and TechnologyChangwon51543 Korea Electric Machines and Drives Research Center Korea Electrotechnology Research InstituteChangwon51543 South Korea the Electrical Engineering Department Kyungnam UniversityChangwon51767 South Korea

In this paper,a design is presented for a high-speed,high-power motor for a four-legged robot actuator that was optimized using the weighted sum method(WSM)based on the Taguchi method,and the response surface method(RSM).First,output torque,torque constant,torque ripple,and efficiency were selected as objective functions for the optimized *** sampling method was implemented to use a mixed orthogonal array and the single response characteristics of each objective function were compared using the Taguchi ***,to consider the multi-response characteristic of the objective functions,WSM was ***,the 2D finite element analysis result of the RSM was compared with that using the ***,an experiment was carried out on the manufactured motor and the optimized model is presented here.

关键词： Four-legged robot Multiphysics analysis Optimized design Surface mounted permanent magnet synchronous motor

Microfluidic dual loops reactor for conducting a multistep reaction

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Frontiers of Chemical Science and Engineering 2018年第2期12卷 239-246页

作者： Si Hyung Jin Jae-Hoon jung Seong-Geun Jeong Jongmin Kim tae jung Park Chang-Soo Lee Department of Chemical Engineering Chungnam National University Daejeon 34134 Korea Lotte Chemical R&D Center Daejeon 34110 Korea Department of Chemistry Chung-Ang University Seoul 06974 Korea

Precise control of each individual reaction that constitutes a multistep reaction must be performed to obtain the desired reaction product efficiently. In this work, we present a microfluidic dual loops reactor that enables multistep reaction by integrating two identical loop reactors. Specifically, reactants A and B are synthesized in the first loop reactor and transferred to the second loop reactor to synthesize with reactant C to form the final product. These individual reactions have nano-liter volumes and are carded out in a stepwise manner in each reactor without any cross-contamination issue. To pre- cisely control the mixing efficiency in each loop reactor, we investigate the operating pressure and the operating frequency on the mixing valves for rotary mixing. This microfluidic dual loops reactor is integrated with several valves to realize the fully automated unit operation of a multistep reaction, such as metering the reactants, rotary mixing, transportation, and collecting the product. For proof of concept, CdSeZn nanopartieles are successfully synthesized in a microfluidic dual loops reactor through a fully automated mukistep reaction. Taking all of these features together, this microfluidic dual loops reactor is a general microfluidic screening platform that can synthesize various materials through a multistep reaction.

关键词： microfluidics multistep reaction rotary mixing nanoparticle

Analysis of Determinants for an Enhanced and Long-lasting Coastal Convective System by Means of a Case Study(26 July 2011)

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Advances in Atmospheric Sciences 2019年第12期36卷 1327-1339页

作者： jung-tae LEE Dong-In LEE Shingo SHIMIZU Cheol-Hwan YOU New and Renewable Energy Resource Center Korea Institute of Energy ResearchDaejeon 34129Republic of Korea Department of Environmental Atmospheric Science Pukyong National UniversityBusan 48513Republic of Korea Storm Floodand Landslide Research DepartmentNational Research Institute for Earth Science and Disaster ResilienceTsukuba 305-0006Japan

A precipitation system developed continuously along the western coastline of the Korean Peninsula and created considerable precipitation both along the coast and inland on 26 July 2011. In this study, the causes for this nearshore convective system are investigated from observations and the results of model experiments. Three-dimensional radar fields clearly show that a change of wind at the surface border played an important role in the development of the nearshore convection system. The simulation results, which are very similar to the observations, show that the surface border generated and maintained the convergence zone. The roughness change enhanced the convergence, and the interaction between the deepening cold pool and downward flow maintained the convergence zone. The surface mechanical discontinuity affected by the roughness change between sea and land formed the convergence (gradient of wind stress), which induced momentum transfer to the upper layer. The cold pool created a steep gradient of potential temperature and provided the reason for the propagated convergence zone with the downward flow. The maximum value of the surface change factor, which comprises the influencing factors for the long-lasting convective system, reflects the enhancement of the system at the coast.

关键词： coastal precipitation roughness convergence zone cold pool propagation downward flow

Fabrication of Barrier Ribs for PDP by Capillary Infiltration Process and Their Sintering Behavior

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Journal of Rare Earths 2004年第Z2期22卷 98-101页

作者： tae jung Tang Hak Nynu Choi Chan Hyoung Kang Yong Seog Kim Department of Materials Science and Engineering Hongik UniversitySeoul 121-791Korea Department of Materials Science and EngineeringHongik UniversitySeoul 121-791Korea Department of Advanced Materials EngineeringKorea Polytechnic University Shihung-CityKyonggi-DoKorea Department of Materials Science and EngineeringHongik UniversitySeoul 121-791Korea

Closed-cell type barrier ribs such as meander, honeycomb, SDR, and waffle types were produced using capillary molding process. Sintering of the ribs revealed that the ribs with asymmetric geometry such as meander and SDR type became distorted severely by the sintering process, but the ribs with symmetric geometry such as honeycomb and waffle type maintained their green state morphology. After sintering, the ribs were coated with green phosphor using osmosis coating process and its luminance characteristics were evaluated. The results indicated that the luminance and its efficiency is improved by using closed-cell type ribs with the new phosphor forming technology.

关键词： PDP close celled barrier ribs sintering distortion

Fabrication of Polythiophene Patterns through Blending of a Thermally Curable Polythiophene with Poly(methyl methacrylate) and Selective Thermal Curation

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Chinese Journal of Polymer Science 2017年第3期35卷 422-433页

作者： Mushtaque A.Memon Jin-hua Sun Hee-tae jung 闫寿科耿建新 State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology Beijing 100029 China Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100190 China National Research Laboratory Department of Chemical and Biomolecular Engineering (BK-21) Korea Advanced Institute of Science and Technology 373-1 Guseong-dong Yuseong-gu Daejeon 305-701 Korea

In this study, we demonstrate a novel method for fabricating polythiophene patterns, i.e., cylindrical holes and cylinders, through blending of a thermally curable polythiophene carrying with tertiary ester groups(PT-tert-ESTER) and poly(methyl methacrylate)(PMMA), followed by thermal conversion of the PT-tert-ESTER to an insoluble polythiophene via low-temperature cleavage of the tertiary ester groups and removal of the PMMA component via ultraviolet degradation. We show that the surface polarity of substrates, the mass ratio of PT-tert-ESTER to PMMA in the blend solutions as well as the concentration of the blend solutions strongly influence the formation of the polythiophene patterns. Cylindrical holes are more readily formed on less polar substrates when a PT-tert-ESTER dominated blend solution is used, while cylinders are more readily formed on more polar substrates when a PMMA dominated blend solution is used. Moreover, the diameters of both the cylindrical holes and the cylinders decrease as the PT-tert-ESTER concentration is increased in the respective ranges of the PT-tert-ESTER/PMMA ratios where the patterns are formed. Grazing incident X-ray diffraction data have indicated that the patterning of the PT-tert-ESTER component in the blend films improves the crystallinity of PT-tert-ESTER as well as the molecular packing of the insoluble polythiophene in the resultant patterned polythiophene films.

关键词： Polythiophene Patterns Cylindrical holes Cylinders Blending

Ni, Co-double hydroxide wire structures with controllable voids for electrodes of energy-storage devices

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Journal of Materials Science & Technology 2020年第20期52卷 126-135页

作者： Jin Kyu Kim Chang Soo Lee Jae Hun Lee jung tae Park Jong Hak Kim Department of Chemical and Biomolecular Engineering Yonsei University50 Yonsei-roSeodaemun-guSeoul 03722Republic of Korea Department of Chemical Engineering Konkuk University120 Neungdong-roGwangjin-guSeoul 05029Republic of Korea

We re port the facile synthesis of Ni,Co-double hydroxide wire(NCHW)-based electrodes directly grown on a conductive substrate via a hydrothermal *** NCHW nanostructures were grown on Ni foam,and the growth was controlled using different compositions of solvents(ethanol and water).With increasing volume ratio of ethanol to water,the density of the wires decreased,and the spatial voids between the wires *** formation of large empty spaces improved the electrochemical performance because the exposure of a large surface area of the structure to the electrolyte resulted in a large number of active sites and facile electrolyte penetration into the *** different NCHW structures were ascribed to the pivotal role of the solvent in the urea hydrolysis;the solvent triggered the formation of hydroxides during the hydrothermal *** electrochemical performance of the NCHW electrodes was investigated via galvanostatic charge/discha rge tests,cyclic voltammetry,and electrochemical impedance *** highest specific capacitance was 1694.7 m F/cm^2 at 2 mA/cm^2,with excellent capacitance retention of 81.5% after 5000 *** superior electrochemical performance of the NCHW electrodes is attributed to the large number of active sites and facile electrolyte diffusion into the structure,due to the well-organized structure with an optimized density of nanowires and large voids between the wires.

关键词： Ni,Co-double hydroxide Nanowire Electrode Energy-storage device Supercapacitor

Impregnation approach for poly(vinylidene fluoride)/tin oxide nanotube composites with high tribological performance

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Journal of Materials Science & Technology 2020年第2期37卷 19-25页

作者： Min Su Park Jin Kyu Kim Tong-Seok Han jung tae Park Jong Hak Kim Department of Chemical and Biomolecular Engineering Yonsei University50 Yonsei-roSeodaemun-guSeoul03722Korea Department of Civil and Environmental Engineering Yonsei University50 Yonsei-roSeodaemun-guSeoul03722Korea Department of Chemical Engineering Konkuk University120 Neungdong-roGwangjin-guSeoul05029Korea

We report a composite material with the high tribological performance,which consists of onedimensional SnO2 nanotubes(ST)and a high molecular weight poly(vinylidene fluoride)(PVDF)matrix in terms of *** of PVDF in N,N-dimethylformamide(DMF)resulted in a facile penetration of PVDF into the inner hollow voids of ST,leading to the close *** between PVDF and ST results in a beneficial effect on the chain arrangement of PVDF,providing anα-phase with better tribological *** ST incorporation,the friction coefficient decreased by 85.0%to 0.408,and the specific wear rate decreased by 69.1%to 0.412,demonstrating the pivotal role of ST as a self-lubricating material due to a large interactive area and PVDF chain rearrangement.

关键词： SnO2 nanotube Composite Friction coefficient Wear rate